Elastic nonwoven fabric, process for producing the same, and textile product comprising the elastic nonwoven fabric

Abstract

(1) An elastic nonwoven fabric and a fiber product using the elastic nonwoven fabric, the elastic nonwoven fabric containing a crystalline resin composition containing low crystalline polypropylene and high crystalline polypropylene, the low crystalline polypropylene satisfying items (a) and (b) below, and a crystallization temperature (Tc) of the crystalline resin composition measured with a differential scanning calorimeter (DSC) being from 20 to 100° C.: (a) a melting point (Tm-D) being from 0 to 120° C., which is defined as a peak top of a peak observed on the most high temperature side of a melt endothermic curve obtained by maintaining at −10° C. for 5 minutes and increasing in temperature at 10° C. per minute in a nitrogen atmosphere with a differential scanning calorimeter (DSC); and (b) a stereoregularity index ([mm]) being from 50 to 90% by mol; (2) an elastic nonwoven fabric and a fiber product using the elastic nonwoven fabric, the elastic nonwoven fabric being produced by using a crystalline resin composition containing low crystalline polypropylene satisfying items (c) to (h) below, and a releasing agent: (c) [mmmm]=20 to 60% by mol; (d) [rrrr]/(1−[mmmm])≦0.1; (e) [rmrm]>2.5% by mol; (f) [mm]×[rr]/[mr] 2 ≦2.0; (g) mass average molecular weight (Mw)=10,000 to 200,000; and (h) molecular weight distribution (Mw/Mn)<4; and (3) an elastic nonwoven fabric and a fiber product using the elastic nonwoven fabric, the elastic nonwoven fabric containing core/shell type composite fibers containing low crystalline polypropylene satisfying the items (c) to (h) have excellent elastic recovery property and pleasant texture without stickiness.

1 : An elastic nonwoven fabric comprising a crystalline resin composition that comprises a combination of from 80 to 99% by mass of low crystalline polypropylene and from 20 to 1% by mass of high crystalline polypropylene,
 wherein a crystallization temperature (Tc) of the crystalline resin composition measured with a differential scanning calorimeter (DSC) is from 20 to 100° C.:   a melting point (Tm-D) of the low crystalline polypropylene is from 0 to 120° C., defined as a peak top of a peak observed on a highest temperature side of a melt endothermic curve obtained by maintaining at −10° C. for 5 minutes and increasing in temperature at 10° C. per minute in a nitrogen atmosphere with a differential scanning calorimeter (DSC); and   (b) a stereoregularity index of the low crystalline polypropylene is from 50 to 90% by mol.   
     
     
         2 : The elastic nonwoven fabric according to  claim 1 , wherein the crystalline resin composition comprises a combination of from 85 to 99% by mass of the low crystalline polypropylene and from 15 to 1% by mass of the high crystalline polypropylene. 
     
     
         3 : The elastic nonwoven fabric according to  claim 1 , wherein
 a meso pentad fraction [mmmm] of the low crystalline polypropylene is from 20 to 60% by mol;   a quotient [rrrr]/(1 [mmmm]) of a racemic pentad fraction [rrrr] divided by a quantity (1−[mmmm]) in the low crystalline polypropylene is less than or equal to 0.1;   a racemic-meso-racemic-meso pentad fraction [rmrm] of the low crystalline polypropylene is greater than 2.5% by mol;   a quotient [mm]×[rr]/[mr] 2  of a product of a meso triad fraction [mm] and a racemic triad fraction [rr] divided by square of a meso-racemic triad fraction [mr] 2  of the low crystalline polypropylene is less than equal to 2.0;   a mass average molecular weight (Mw) of the low crystalline polypropylene is from 10,000 to 200,000; and   a molecular weight distribution (Mw/Mn) of the low crystalline polypropylene is less than 4.   
     
     
         4 . (canceled) 
     
     
         5 : The elastic nonwoven fabric according to  claim 1 , wherein
 a melting point (Tm-D) of the high crystalline polypropylene is 155° C. or more, defined as a peak top of a peak observed on a highest temperature side of a melt endothermic curve obtained by maintaining at −10° C. for 5 minutes and increasing in temperature at 10° C. per minute in a nitrogen atmosphere with a differential scanning calorimeter (DSC).   
     
     
         6 - 11 . (canceled) 
     
     
         12 : A fiber product comprising the elastic nonwoven fabric according to  claim 1 .